The present invention relates to an anti-skid device, particularly for motor vehicles with pneumatic tires when driven on ice and snow, which comprises a fixing disk fastenable to the wheel disk or rim, which is provided with openings for fastening to rim screws, wheel studs or the like and a supporting disk held and lockable on the fixing disk by means of a retaining ring and which has a plurality of equidistant, radially disposed anti-skid arms formed from a pre-bent profile of plastic or some other suitable material, which overlap the tire tread and carry internally and externally at the free ends thereof a gripping profile, having spikes or metal bodies on the outside, as well as an adaptor for screwheads and the like.
Winter tires or so-called friction tires are used when driving vehicles in winter on snow-covered uphill and downhill gradients. Snow chains are not very popular, because it is often difficult to fit them to the vehicle tires and they must be used in such a way that the road is not damaged, i.e the snow chains have to be removed on dry road sections following the snow or ice-covered sections. In addition, when travelling on dry roads, snow chains are subject to a high degree of wear and do not permit high speeds. Particularly in the case of roads which become covered with ice at short notice, i.e. ice surfaces produced by drizzling rain falling on frozen road surfaces, snow chains and winter tires are often not available. It is also not always possible to use spiked tires. Apart from snow chains and winter tires starting aids are known, but cannot replace snow chains and winter tires. These starting aids, which comprise clamp straps mounted on the tires, merely serve to permit a vehicle to be driven a short distance out of mud or snow.
An anti-skid device, particularly for vehicle wheels with pneumatic tires when driven on ice and snow, which comprise a fixing disk which can be fastened to the wheel disk or rim and provided with openings for fastening to the rim screws, wheel studs and the like, together with a supporting disk held and lockable by means of a retaining ring on the fixing disk and having a plurality of equidistantly radially disposed anti-skid arms formed from a pre-bent profile made from plastic or another suitable material engaging over the tire tread and carrying externally and internally on their free ends a gripping profile, while having externally fitted spikes or metal bodies, is known from German utility model 83 27 385.
For attaching the supporting disk, this known anti-skid device has a fixing disk which can be connected to the wheel disk or rim and which is provided with lockable fastenings for the supporting disk, the fixing disk still remaining connected to the wheel disk or rim when the anti-skid device is not required. The supporting disk has a central opening, while the circular fixing disk centrally carries a circular hub having, a smaller diameter than the fixing disk, said hub having circumferentially at a distance from the fixing disk and adjacent to its upper edge, a plurality of bulge-like shoulders with sliding and guiding paths arranged below the same and tapering conically from the insertion openings in the direction of the hub circumference and which carry the supporting disk with the anti-skid arm surrounding the hub and which is secured by means of a retaining ring mounted on the hub, having locking webs insertable into the sliding and guiding paths of the hub and bringing about a bayonet-type locking, with conically tapering portions extending towards the insertion openings and having on its inner wall face at least one leaf spring-like latch which, in the locked position of the retaining ring of the fixing disk, engages in a recess in the hub circumference and is supported against undesired unlocking by a stop member and can be transferred by means of an unlocking key from the locking position into an unlocking position.
With such an anti-skid device, the fixing disk with the specially constructed hub always remains on the wheel disk or rim, while for the operating state of the anti-skid device, the supporting disk with the anti-skid arms is mounted on the fixing disk and is locked thereto by means of the retaining ring. In order to be able to fix the fixing disk to the wheel disk or rim, the fixing disk is provided with openings for fixing to rim screws, wheel studs or the like. For this purpose the fixing disk has a predetermined number of openings for attaching to rim screws, wheel studs, etc. It is disadvantageous that for stability and dimensional reasons, the fixing disk cannot have a plurality of differently arranged openings for receiving the rim screws or wheel studs, so as to be able to attach the fixing disk to wheel disks or rims where there are other dimensions and associations for the rim screws or wheel studs. However, it is not economic to keep in stock a large number of differently constructed fixing disks, so as to permit adaptability of the anti-skid device to the most varied wheel disks or rims. The attaching of the fixing disk to the wheel disks or rims takes place by means of rim screws or wheel studs.
For attaching such an anti-skid device, as well as wheel sleeve nuts, wheel split nuts, particularly shields and measuring devices, it is necessary to have a large number of special wheel screws and nuts with different threads, thread lengths, balls, cones, shuttles, flat collars, arbor tapers, width across flats and materials. Frequently the attaching elements change in the case of new vehicle types.